Is a rubidium cell with long decay time always useful for generating a non-classical photon pair?

TL;DR

This paper demonstrates that a rubidium cell with a long decay time is not suitable for generating non-classical photon pairs via four-wave mixing, supported by experimental and theoretical analysis.

Contribution

It provides the first detailed theoretical analysis explaining why long decay time rubidium cells are ineffective for non-classical photon pair generation via D2 transition.

Findings

Long decay time rubidium cells do not produce non-classical photon pairs in the studied configuration.

Theoretical analysis aligns with experimental results, explaining the inefficiency.

The work offers guidance for future research in quantum light sources.

Abstract

We experimentally find an interesting and unexpected thing: a rubidium cell with long decay time can not be used to generate a non-classical correlated photon pair via the D2 transition of $^{87}$Rb using four-wave mixing configuration [Opt. Express {\bf 16}, 21708 (2008)]. In this work, we give a detail theoretical analysis on the EIT of hot $^{87}$Rb with different ground decay time, which shows a probable reason why a rubidium cell with long decay time is not a useful candidate for preparation of a non-classical photon pair via the D2 transition. The simulations agree well with the experimental results. We believe our find is very instructive to such kind of research.